I usually siphon out the sand and replace with new sand. The sand that I siphon out I wash and let dry out, then reuse it when I have to clean the sand again. It’s tedious but that’s the only way really to keep the sand “clean.”
I don't clean my sand. The substrate, especially the surface area that has access to oxygen houses beneficial bacteria that helps keep the tank balanced and clean.
I know this might not be the answer you're looking for but still wanted to give my honest answer lol. I hope you don't mind a different perspective!